Stabilized stool support



Jan. 24, 1961 E. w. MaoKNlGHT STABILIZED sTooL SUPPORT Filed 001). 1'7, 1955 types of chairs for patients,

United States Patent O STABILIZED STOOL SUPPORT Edgar W. MacKnight, deceased, late of San Leandro, Calif., by Bonna MacKnigbt, executrix, 159 Bowling Green, San Leandro, Calif., assignor, by courtdecree, to Bonna MacKnight Filed Oct. 17, 1955, Ser. No. 540,838

8 Claims. (Cl. 155-81) The present invention relates to dental chairs or other and more particularly to auxiliary stool assemblies of the types employable by dentists or other operators in conjunction with such chairs.

When utilizing an auxiliary stool assembly while operating on a patient, conditions for the operator must be such as to enable him to work with exacting care and precision, and toward this end, he must be assured that both he and the patient are stably supported, both with respect to the oor and with respect to each other. While the equipment itself might be sufcien-tly well designed to lend itself to the fulllment of such conditions, any irregularities in the oor surface upon which the equipment rests, may be such as to preclude the realization of such objective, with the result that during the course of an operation, the patients chair may tilt or rock or otherwise shift from its original position and thereby cause some concern to either the operator or patient.

Among the objects of the present invention are:

(l) To provide a novel and improved arrangement of patients chair and auxiliary stool assembly, to assure stability under all conditions;

(2) To provide a novel and improved auxiliary stool assembly for use with a patients chair, which assembly is characterized by a high degree of stability when so used;

"(3) To provide a novel and improved auxiliary stool assembly for use with a patients chair, which stool assembly is not only stable, but when coupled to the patients chair will assure stability thereof also;

(4) To provide a novel and improved auxiliary stool assembly of the cantilever type having a high degree of stability in use;

(5) To provide a novel and improved auxiliary stool assembly of the cantilever type for use with a patients chair, which stool assembly when so used, will assure stability of such chair also.

Additional objects of the invention will be brought out l in the following description of a preferred embodiment of the same taken in conjunction with the accompanying drawings wherein,

Figure 1 is a three dimensional view of the auxiliary stool assembly in its present preferred form, and depicting it in association with a patients chair;

Figure 2 is a fragmentary view in section through the arrangement of auxiliary stool assembly and patients chair depicted in Figure 1, to bring out the manner in which one is coupled to the other;

Figure 3 is a fragmentary view in elevation looking in the direction of the arrow 3 of Figure 2;

Figure 4 is a diagram depicting the manner in which the present invention assures stability to both the auxiliary stool assembly and the patients chair When the two are vcoupled together.

While the present invention will function to stabilize the patients chair regardless of the type of auxiliary stool assembly which is coupled thereto, it is particularly suitable for auxiliary stool assemblies of the cantilever Patented Jan. 24, 1961 type, in view of the normal tendency of such type of stool assembly to develop moments in the direction of tilting the patients chair, and would therefore respond adversely when the nature of the floor surface is such as to encourage instability. Accordingly, the present inyvention will be described in connection with a cantilever stool assembly, and more particularly the cantilever stool assembly illustrated and described in the application 0f Edgar W. MacKnight, Serial No. 451,805, filed Aug. 16,

1954, now Patent No. 2,848,037, issued August 19, 1958, on which the present invention may be considered to be an improvement, though it by no means is limited in its applications, to this particular stool assembly.

Referring to the drawings for a description of the invention in its preferred form, the cantilever type stool assembly 1 in general involves a base sub-assembly 3 on which there is rigidly mounted a pivot post 5. Surrounding the pivot post and spaced by a sleeve 7, are a pair of bearings 9, 11 on which to rotatably mount a hub 13 from which extends a radial arm 15, preferably at a slightly upwardly directed angle in respect to the horizontal. The radial arm, at its free end, terminates in a collar 17 within which is fixed the outer tubular member 19 of a telescopically adjustable standard or post 21.

The inner telescopic member 23 is preferably a tubular member which is adjustable as to elevation within the outer telescopic member, and these adjustments may be maintained by a sui-table manually releasable friction lock 25.

The inner telescopic member carries a seat assembly 27, which preferably is of the type forming the subject matter of application Serial No. 377,349, filed Aug. 10, 1953, now abandoned.

To provide adequate lanchorage for the stool assembly and prevent relative creeping between the stool assembly and the patients chair, the base of the patients chair, at the flange thereof, is clamped to the stool assembly by a sectionalized ring 29 of channel sections, forming part of the base sub-assembly of the cantilever structure, whereby the full weight of the patients chair, plus any occupant thereof, will serve to anchor the auxiliary stool assembly, and support the dentist or other operator there- Such ring includes an anchor portion in the form of a crescent shaped channel section 31 having an arcuate inner edge to receive the flange 33 of the base 35 of the patients chair. Backing this chanel section and welded thereto along the middle portion, is a substantially rectangular base plate 37, While welded to the upper surface of this crescent channel section and overhanging the base plate is a supporting strip 39 for the pivot post 5. The space between this supporting strip and the base plate, immediately below the pivot post is occupied by a spacer block 41, leaving suiicient room for the reception of the edge of a floor mat 43 such as that commonly employed by a dentist over the work area occupied by him in his work.

The pivot post is of cylindrical form having a bore therethrough, the post being counter-bored for the reception of a bolt 45 which extends through the supporting strip 39 and spacer block 41 and thereadedly engages the base plate 37 to securely anchor the pivot post.

A screw 47 through the inner edge of the supporting strip, is adapted to pressure engage the flange of the base of the patients chair with suflicient grip to securely retain the ange in the arcuate chanel section portion of the encircling ring.

An additional pair of ring channel sections 49, 51 are required to complete the encirclement of the flange of the patients chair. These may be removably secured to the crescent shaped section 31 in any suitable manner, as for example by a tongue and slot inter-lock as depicted in previously mentioned pending application Serial No. 451,805. Each of these two sections terminates in an ear, one such ear 53 having an Unthreaded bolt passage therethrough, while the other one 55, has a threaded passage to receive the threaded end of a bolt 57 passing through the unthreaded passage. This provides a simple expedient for enabling installation and securing of the sectionalized ring to the iiange of patients chair.

When so coupled, the patients chair and the auxiliary stool assembly become a unit, thereby assuring maintenance of a fixed relationship between the patients chair and the auxiliary stool assembly at all times.

The essence of the present invention in its preferred form, resides in altering the aforementioned subassembly so as to bring about two important functional changes, which cooperate to fulfill the objects of the present invention. This is accomplished through the simple expedient of a oor plate 59 of substantial length disposed beneath and welded or otherwise affixed to the base plate 37, transversely of a median line 6) through the subassembly including the crescent shaped channel section. This oor plate is preloaded by turning down its ends so as to engage the floor along its turned down edges. This will result in the clamping means being elevated above the plane of contact of the floor plate, in the absence of pressure thereon. When the stool assembly and the patients chair are coupled in the manner indicated, however, the weight of the chair will depress the subassembly somewhat, even to the extent at times, of caus ing the clamping means to contact the floor. In any event, the patients chair and auxilary stool assembly, as a unit, will be supported predominantly at three widely spaced locations, namely along each turned down edge of the iioor plate and at the remotest point of the ange of the patients chair, identified by the location of the clamping bolt 57. From this, it will be apparent that with the patients chair and stool assembly thus supported, any normal floor irregularities lying intermediate these locations of rest, can exercise no adverse inuence on the stability of the arrangement; and thus regardless of the type of auxiliary stool assembly that may be utilized, overall stability will be assured, insofar as door irregu larities might be concerned.

As previously indicated, the problems of instability in a normal installation become vastly more complicated when the type of auxiliary stool assembly is of the cantilever type, because any change in load on such type of stool assembly, or any shift of the stool assembly seat, normally would have a tendency to disturb the patients chair, and even where the problem of floor irregularities is not encountered. Therefore, though the three location support of the present invention, eliminatesthe problem of floor irregularities, there still remains those problems arising out of the use of a cantilever type stool assembly.

Under the conditions established by the present invention, any theoretical rocking of the patients chair attributable to the use of a cantilever type stool assembly, would necessarily be restricted to certain fulcrum axes determined by the threev locations of support. One such axis would coincide with a line 63 joining the front corners of the floor plate 59. A second such axis would be deiined by a line 65 joining one of the rear corners of the iioor plate with that point on the flange of the patients chair constituting one of the three supporting locations. A third such axis would coincide with a line 67 extending from this ange point to the remaining rear corner of the oor plate.

Whether the Weight of the auxiliary seat assembly plus the operator, act in relationship to one or the other of such axes, will of course depend on the position of the seat and operator at any particular moment. However, it will be shown that rocking of the patients chair about any of these axes cannot occur. The Weight of a patients chair is normally in the neighborhood of four hundred pounds, which, in any event, will greatly outweigh the combined weight of the auxiliary stool assembly and operator, and in most cases by twice that amount. The relative moment arms to the various fulcrum axes, in many positions of the operator, favor the patient chair, and in no instance do they favor the operator to the degree which would permit disturbance of the patients chair with normal movements of the operator. And with a patient in the chair, the assurance against tilting on any of the fulcrum axes is to that extent increased.

Consequently, inasmuch as any oor unevenness or irregularities can, in no respect, adversely aiect the stability of the patients chair or the auxiliary seat assembly, and inasmuch as the weight of the patients chair acting through its moment arm is more than adequate to resist the strains or stresses which may be set up by the operator and auxiliary seat assembly acting through their moment arms, it follows then that stability will be assured at all times even when employing an auxiliary stool assembly of the cantilever type.

llt will be apparent from the foregoing description of the present invention in its preferred form, that the invention fulfills all the obje-cts attributed thereto, and while the same has been described in considerable detail, it is nevertheless subject to alteration and lmodification without departing fro-m the underlying principles involved, and accordingly the protection afforded should not be limited to specific details illustrated and described except as may be necessitated by the appended claims.

What is claimed is:

l. An auxiliary stool assembly for use with a patients chair, said assembly including a base sub-assembly having tloor engaging means of substantial length engaging the tloor at its ends only and substantially symmetrically located with respect to a median line through such subassembly adjacent one edge thereof with the length of the licor engaging means substantially transverse to said median line, and Ipatient chair iiange supporting and securing means elevated above the plane of contact of .said floor engaging means for supporting and securing to said stool assembly, the iiange of the base of such patients chair.

2. An auxiliary stool assembly of the cantilever type for use with a patients chair, said assembly including a base sub-assembly having oor engaging means of substantial length engaging the floor at its ends only and adapted to engage a floor at spaced locations substantially vsymmetrically located with respect to a median line through said sub-assembly adjacent one edge thereof with the length of the iioor engaging means substantially transverse 'to said median line, and patient chair flange supporting and securing means elevated above the plane of contact of said Hoor engaging means and disposed substantially symmetrically of said median line, for supporting and securing to said stool assembly, the flange of the 2base of such patients chair.

3. An auxiliary stool assembly for use with a patients chair, said assembly comprising a base sub-assembly and a superstructure associated therewith, said base subassernbly including oor engaging means of substantial length engaging the iioor at its ends only; adapted for engaging a oor at spaced locations substantially symmetrical with `respect to a median line through said base sub-assembly adjacent one edge thereof with the length of the oor engaging means substantially transverse to said median line, and patient chair Harige supporting and securing means elevated above the plane of contact of said floor engaging means for supporting and securing to said stool assembly, the ange of the base of such patients chair.

4. An auxiliary stool assembly for use with a patients chair, said assembly comprising a base sub-assembly and a cantilever super-structure carried thereby, said base sub-assembly including floor engaging means of substantial length engaging the lioor at its ends only and adapted for engaging a oor at spaced locations substantia-lly symmetrical with respect to a median line through the base sub-assembly adjacent one edge thereof with the length of the oor engaging means substantially transverse to said median line, said iloor engaging means involving a floor plate of substantial length disposed transversely o-f said median line and having its ends turned down to provide localized contact -at each end thereof with such floor, and patient chair flange supporting and securing means elevated above the plane of contact of said floor engaging means for supporting and securing to said stool assembly, the flange of the base of such patients chair.

5. In combination, a patients chair having a base terminating in a flange around the bottom thereof, an auxiliary stool -assembly including a base sub-assembly having oor engaging means of substantial length engaging the floor at its ends only and substantially symmetrically located with respect to a median line through substantially the center of said base sub-assembly adjacent one edge thereof with the length of the floor engaging means substantially transverse to said median line, and patient chair flange supporting and securing means elevated above the plane of contact of said floor engaging means for supporting and securing said patients chair along the flange thereof, said means comprising a crescent shaped channel section included in said base sub-assembly transversely of said median line above the plane of contact of said iloor engaging means and enclosing an arcuate portion of said patients chair flange, whereby said patients chair and auxiliary stool become a unit assembly supported predominantly at three widely spaced locations, two `of which are under the base sub-assembly of said auxiliary stool to the exclusion of said patients chair.

6. In combination, a patients chair having a base terminating in a flange around the bottom thereof, an auxiliary stool assembly including a base sub-assembly having floor engaging means of substantial length engaging the iloor at its ends only and substantially symmetrically located with respect to a median line through substantially the center of said base sub-assembly adjacent one edge thereof with the length of the oor engaging means substantially transverse to said median line, said floor engaging means involving a oor plate of substantial length disposed transversely of said median line and having `its ends turned down to provide contact at each end thereof with such oor, and patient chair flange supporting and securing means elevated above the plane of contact of said floor engaging means for supporting and securing said patients chair along the ange thereof, to imperceptibly tilt said patients chair, whereby the stool assembly and patients chair as Va unit are supported by the floor predominantly at three widely spaced locations, two of which are under the base sub-assembly of said auxiliary stool to the exclusion of said patients chair.

7. In combination, a patients chair having a base terminating in a flange around the bottom thereof, an auxiliary stool assembly of the cantiliver type including a |base sub-assembly having floor engaging means of substantial length engaging the oor at its ends only and substantially symmetrically located with respect to a median line through substantially the center of said base sub-assembly adjacent one edge thereof with the length of the floor engaging means substantially transverse to said median line, said floor engaging means involving a oor plate of substantial length disposed transversely of said median line and having its ends turned down to provide contact at each end thereof with such floor, and patient chair flange supporting and securing means elevated above the plane of contact of said floor engaging means for supporting and securing said patients chair along the ange thereof, said means comprising a crescent shaped channel section included in said base subeassembly transversely of said median line above the plane of contact of said floor engaging means and enclosing an arcuate Iportion of said patients chair ange to imperceptibly tilt said patients chair, whereby the stool assembly and patients chair as a unit are supported by the oor predominantly at three widely spaced locations, two of which are under the base sub-assembly of said. auxiliary stool to the exclusion of said patients chair.

8. An auxiliary stool assembly for use with a patients chair, said assembly including a cantilever type stool having a base assembly of substantial length with floor engageable portions at the ends only thereof for engaging a door at spaced locations substantially symmetrical with respect to a median line through said base assembly adjacent one edge thereof with the length of said base assembly substantially transverse to said median line, and patient chair flange supporting and securing means elevated `above the plane of contact of said oor engageable portions for supporting and securing such patients chair along the flange thereof, whereby said auxiliary stool assembly and said patients chair will form a unitary assembly supported on a floor at three widely spaced locations, two of which will be at the floor engageable portions of said base assembly to the exclusion of such patients chair, to stabilize such unitary assembly of patients chair and auxiliary stool assembly.

References Cited in the le of this patent UNTTED STATES PATENTS 375,954 Robb Ian. 3, 1888 2,449,385 Johnson et al. u Sept. 14, 1948 2,521,031 Alspaugh Sept. 5, 1950 2,596,561 Johnson May 13, 1952 2,650,647 MacKnight Sept. 1, 1953 2,694,439 Murray Nov. 16, 1954 2,848,037 MacKm'ght Aug. 19, 1958 FOREIGN PATENTS 75,517 Denmark fa-"1 Feb. 16, 1953 

